Press the 'Saute' button, and add the olive oil. When the pot is hot, add the ground sausage and brown it until no longer pink, about 3 minutes.

Add onion and garlic and saute for another 3 minutes. Add potatoes, vegetable stock, and oregano and season with salt and pepper. Stir everything.

Lock the lid and turn the valve to 'Sealing'. Cook on manual, pressure set to 'High' for 10 minutes. When the cook time is over, turn off the Instant Pot by pressing the 'Turn Off' button. Carefully quick release the pressure with a wooden spatula by turning the valve to releasing. Make sure you don’t hurt your hands from the steam.